In general, water is used as a heat exchange medium in a variety of equipment and facilities, such as cooling/heating air conditioning facilities, refrigerating and freezing facilities and industrial freezing facilities. In particular, a heat exchanger coil, an evaporating cooling tower or the like of a water cooling condenser or an air conditioner is highly vulnerable to accidents in which a pipe that is exposed to ambient air is fractured due to freezing when the water inside the pipe freezes when the temperature drops below zero, for example, during the winter.
The freeze-fracturing of the pipe in such equipment and facilities causes loss of water resources due to leakage and other losses, such as damage and breakage to the equipment and surrounding facilities. Since it consumes a lot of time and expense to replace and repair the facilities, attempts and measures to effectively prevent freeze-fracturing in advance are demanded.
Although the water inside a closed pipe is not easily frozen when it is flowing, it is easily frozen when the temperature decreases if its flow is stopped. Since water exhibits a volumetric increase of about 10% in the process of changing in phase from liquid to solid, the pipe is subjected to freeze-fracturing, exhibiting a crack or fracture if the pressure of the expansion of water exceeds the endurance strength of the pipe.
Typical attempts to prevent such freeze-fracturing employ a method of installing a heat-retaining article or a heating device inside a pipe, a method of mixing an antifreeze solution, such as brine, into water, a method of keeping water flowing by continuously draining water from the pipe, etc. However, such methods have problems, for example, in that an additional heat-retaining article or heating device must be installed, in that the operation of the heating device consumes a large amount of energy, and in that the drainage of water wastes water resources.
In the meantime, as a device for preventing accidental freeze-fracturing in a pipe, proposed is a safety plug for preventing freeze-fracturing, which transfers the pressure of expansion to the outside by opening/closing a valve using upward/downward movement due to the pressure of expansion, and prevents water from leaking by automatically closing the channel through which water is forced in. However, since the plug is configured such that a tearing member is fractured to drain water when the pressure of expansion is excessive, there is a drawback in that it is disadvantageous in terms of maintenance since time and expense associated with labor and materials are consumed when replacing the broken tearing member with a new one.